1. Technical Field
The present invention relates to power tools; and, more particularly, to an auxiliary power tool base assembly for usage with portable power tools, such as a router, which employ guides and guide rods wherein the auxiliary base assembly can be readily attached to the portable power tools after removal of the guide for enabling the router or other tool and the auxiliary base assembly to be inverted and dropped into a flanged opening in a work table where the opening is complementary to the auxiliary power tool base assembly so as to permit usage of a portable power tool as a stationary table top tool where the only portion of the tool extending above the plane of the work table's top is the cutting implement such as a router bit.
While the present invention finds particularly advantageous use with many conventional portable routers since such tools commonly employ guides and one or more guide rods, as the ensuing description proceeds those skilled in the art will appreciate that other portable power tools such as, merely by way of example, jig saws, circular saws and the like, can be readily modified by the tool manufacturer to incorporate one or more removable guide rods associated with the tool's integral base plate; and, therefore, the present invention can also be used in conjunction with such other modified portable power tools. That is to say, the invention is not limited to use with portable routers. Nevertheless, the invention will herein be described in a non-limiting way in conjunction with a portable power router.
2. Background Art
The prior art is replete with disclosures of a wide variety of power tools including routers and varying support mechanisms heretofore used as stationary table top support arrangements for portable power tools where only the tools' cutting implement extends above the work table top. Typical of such disclosures is that found in U.S. Pat. No. 4,774,986--LaGra wherein the patentee discloses a system more particularly shown in FIGS. 1 and 2 for supporting a router beneath the top of a stationary work table. In this arrangement the router is secured to an adapter plate by means of threaded fasteners passing through the adapter plate and into the router base plate. The adapter plate is dimensioned to drop into a complementally shaped recess in the work table top.
In McCambridge et al U.S. Pat. No. 4,350,193 assigned on its face to Central Quality Industries, Inc., a power tool accessory table is described which is said to enable mounting of a wide range of portable power tools including, for example, a router. In this construction, the router or other power tool is secured to a separable base plate which is then inverted and laid crosswise over an opening formed in a work table top where the base plate rests on a peripheral flange integral with the table top. The patent is principally directed to the flange arrangement for securing the base plate to the table top as contrasted with any specific arrangement for securing the base plate to the power tool.
Murphy U.S. Pat. No. 4,335,765 is of interest for its disclosure of a portable multi-purpose construction table. Again, the table is designed to accept a wide range of portable power tools including routers which may, as shown in FIG. 3, be clamped to the underside of the table top by L-shaped clamps.
Similarly, Nash et al U.S. Pat. No. 4,265,283 assigned on its face to the Triangle Corporation, is of interest for its disclosure of elongate channel shaped brackets and clamps for securing a router or other portable power tool to the underside of a work table. Similar arrangements are also disclosed in Stone U.S. Pat. No. 4,186,784, assigned on its face to Atlantic Container Corporation, and Groehn U.S. Pat. No. 2,799,305.
U.S. Pat. No. 2,615,479--Bearup is of incidental interest for its disclosure of a router bit mounted on a removable insert which is supported in a work table top opening; but, in this instance, the router bit is geared to a drive shaft for a table saw. Snow U.S. Pat. No. 4,312,391 is similarly of incidental interest for its disclosure of an adapter permitting mounting of a router on the arm of a radial saw.
In general, each of the foregoing proposed approaches for mounting portable routers on a stationary work table employs clamps, mounting brackets, threaded fasteners and similar devices for securing the router in place. Consequently, these devices are difficult and time consuming to assemble and disassemble. Moreover, they are not particularly stable or safe since there is a tendency for the clamps, mounting brackets, threaded fasteners and the like to loosen as a result of vibrations inherently set up during usage of the tool.
Cowman U.S. Pat. No. 4,718,468, assigned on its face to Black & Decker, Inc., while not related to devices for securing routers to a fixed work table top, is nonetheless of general interest for its disclosure of a relatively conventional present-day router construction available from a number of manufacturers. In this particular instance, the router includes a base plate to which are removably secured a pair of parallel guide rods which are here used to support a router guide.